Expression, purification and characterization of N-glycosylation mutant human IFN-λ1 in Pichia pastoris / 生物工程学报

IFN-λ1 is a member of a new family of interferons called type Ⅲ IFNs with similar functions to type ⅠIFNs. Previously we obtained recombinant soluble human rhIFN-λ1 from Pichia pastoris. However, the hyper-glycosylation from P. pastoris brings immunogenicity and low purification recovery rate. To overcome this disadvantage, in this study, we constructed an rhIFN-λ1 mutant (rhIFN-λ1-Nm) devoid of the potential N-glycosylation sites by site-directed mutagenesis. rhIFN-λ1-Nm was successfully expressed and secreted extracellularly in P. pastoris (GS115) using methanol inducible AOX1 promoter with α-mating factor signal sequence. rhIFN-λ1-Nm was purified and characterized. There was no significant difference between rhIFN-λ1-Nm and rhIFN-λ1 in structure and bioactivity. The molecular weight was low after N-glycosylation mutation whereas the glycosylation was much lower. The mutational rhIFN-λ1 (rhIFN-λ1-Nm) could legitimately be developed as substitutes for rhIFN-λ1, and thus it may be developed into a more promising therapeutic reagent in the future.

Nucleocapsid protein from porcine epidemic diarrhea virus isolates can antagonize interferon-λ production by blocking the nuclear factor-κB nuclear translocation / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Porcine epidemic diarrhea virus (PEDV) is a highly infectious pathogen that can cause severe diseases in pigs and result in enormous economic losses in the worldwide swine industry. Previous studies revealed that PEDV exhibits an obvious capacity for modulating interferon (IFN) signaling or expression. The newly discovered type III IFN, which plays a crucial role in antiviral immunity, has strong antiviral activity against PEDV proliferation in IPEC-J2 cells. In this study, we aimed to investigate the effect of PEDV nucleocapsid (N) protein on type III IFN-λ. We found that the N proteins of ten PEDV strains isolated between 2013 and 2017 from different local farms shared high nucleotide identities, while the N protein of the CV777 vaccine strain formed a monophyletic branch in the phylogenetic tree. The N protein of the epidemic strain could antagonize type III IFN, but not type I or type II IFN expression induced by polyinosinic-polycytidylic acid (poly(I:C)) in IPEC-J2 cells. Subsequently, we demonstrated that the inhibition of poly(I:C)-induced IFN-λ3 production by PEDV N protein was dependent on the blocking of nuclear factor-κB (NF-κB) nuclear translocation. These findings might help increase understanding of the pathogenesis of PEDV and its mechanisms for evading the host immune response.

Construction of a eukaryotic expression system of IFN-λ and evaluation of bio-functions mediated by the system product / 军事医学

Objective To construct a eukaryotic expression system of IFN-λ,examine the expression of IFN-λand evaluate its bio-functions including anti-proliferation and anti-viral activity.Methods The genes of human IFN-λ1 /2 (hIFN-λ1 /2)were cloned from the mRNA of poly I∶C treated HuH-7 cells.The PCR product was examined with DNA sequencing.The genes of IFN-λ1 /2 were sub-cloned into pcDNA3 vector.The correct insertion of the gene IFN-λ1 /2 was identified with enzyme digestion.The constructed pcDNA3-IFN-λ1 /2 plasmids were transfected into COS-7 cells and IFN-λ1 /2 protein was checked in the supernatant and lysis of transfected cells using Western blotting analysis.The human esophageal carcinoma YES5 and T.Tn cells were treated with the IFN-λ1 /2 from the transfected cells and the proliferation of carcinoma cells were measured with CCK-8 kit.In the treated carcinoma cells,the apoptosis and antivirus related molecules such as caspase-3,ISG15 and MxA was analyzed with Western blotting or Quantitative real time PCR.Results The sequence of hIFN-λ1 /2 fragment matched that of the gene bank and the gene of the cytokines was inserted into pcDNA3 vector correctly.With Western blotting analysis,IFN-λ1 /2 protein was detected in the pcDNA3-IFN-λ1 /2 transfected COS-7 cells.The IFN-λ1 /2 from the transfected COS-7 cells inhibited the growth of YES5 and T.Tn cells, activated apoptosis related caspase-3,and up-regulated the anti-virus gene expression of ISG15 and MxA.Conclusion COS-7 cells can express IFN-λ1 /2 after transfection with pcDNA3-IFN-λ1 /2,suggesting that eukaryotic expression system of IFN-λis established.IFN-λ1 /2 from the system can perform bio-functions,such as proliferation inhibition,apoptosis induction and anti-viral gene up-regulation,which indicates that the system can contribute to further investigations of IFN-λbio-activity and its clinical application.

A recombinant adenovirus vector expressing human IFN-λ1 inhibits the growth of orthotopic gastric cancer and its possible mechanism / 中华微生物学和免疫学杂志

Objective To investigate the inhibitory effects of a recombinant adenovirus vector ex-pressing human IFN-λ1 ( r-Ad-hIFN-λ1) on the growth of orthotopic gastric cancer and to analyze its possi-ble mechanism in a nude mice model of orthotopic human gastric carcinoma .Methods Orthotopic trans-plantation was performed to establish the nude mice model of orthotopic gastric cancer .Thirty mice were ran-domly divided into three groups including PBS control group , Ad-Lac Z empty vector group and r-Ad-hIFN-λ1 experiment group .The mice in each group were given the corresponding interventions once a week for three times.The sizes of tumor were detected by using B-mode ultrasound at different time points to draw growth curves .The expression of IFN-λ1 at mRNA level in skeletal muscle tissues was analyzed by RT-PCR.Western blot assay and immunohistochemical staining were used to detect IFN-λ1 protein in gastric tumor samples .The apoptosis of cells in paraffin-embedded tumor tissues was detected by TUNEL .The per-centages of natural killer ( NK) cells in spleen tissues were analyzed by flow cytometry .Results Compared with control group and empty vector group , the mice in r-Ad-hIFN-λ1 experiment group showed the smallest tumor size [(331.25±6.00) mm3, (322.92±5.92) mm3 vs (248.39±7.60) mm3; P<0.05].hIFN-λ1 was transfected into skeletal muscle successfully and expressed in gastric cancer tissue .Highly expressed hIFN-λ1 was observed in cytoplasm of tumor cells from experiment group by immunohistochemical staining . The apoptotic index of tumor tissues for experiment group was 0.700±0.059 which was significant different from that of control group (0.271±0.026, P<0.05) and empty vector group (0.333±0.028, P<0.05). The percentage of NK cells in spleens from mice in experiment group [(26.49±1.89)%] was significantly higher than that of control group [(13.94 ±1.31)%, P<0.05)] and empty vector group [(19.12 ±1.69)%, P<0.05)].Conclusion Transfection of r-Ad-hIFN-λ1 and expression of hIFN-λin skeletal muscle could significantly inhibit the growth of gastric cancer by inducing tumor cells ′apoptosis and enhan-cing NK cells.

Effects of hIFN-λ1 recombinant adenovirus on proliferation of gastric adenocarcinoma cell line and its mechanism / 中华微生物学和免疫学杂志

Objective To explore the effects of Ad-hIFN-λ1 recombinant adenovirus on prolifera-tion of gastric adenocarcinoma cell line SGC-7901 and its mechanism .Methods Ad-hIFN-λ1 recombinant adenovirus and empty plasmid Ad-LacZ were respeetively transfated to human gastric adenocarcinoma SGC-7901 cells.The proliferation of transfected cells was detected by MTT assay .IFN-λ1 gene expression at mR-NA and protein levels in the cells were measured by RT-PCR analysis and immunofluorescence assay , re-spectively .Tunel assay and flow cytometry were used to analyze the rate of cell apoptosis .Results The proliferation of gastric adenocarcinoma SGC-7901 cells were significantly inhibited with Ad-hIFN-λ1 inter-vention in accordance with highly expressed IFN-λ1 at mRNA and protein levels , respectively .The apoptosis rate of Ad-hIFN-λ1 transfected cells was markedly higher than that of the empty plasmid Ad-LacZ group and PBS blank control group .Conclusion The expression of hIFN-λ1 could be detected after transfection of Ad-hIFN-λ1 recombinant adenovirus into gastric adenocarcinoma SGC-7901 cells.Ad-hIFN-λ1 could signifi-cantly inhibit the proliferation of gastric adenocarcinoma SGC-7901 cells by promoting the apoptosis of cancer cells.

Preliminary study on the biological functions of interferon-λ in human esophageal carcinoma cells / 中华微生物学和免疫学杂志

Objective To investigate the biological function of IFN-λ in 7 human esophageal carcinoma cells. MethodsThe gene expression of IL-28α, IL-10β and antiviral molecule was examined with PCR. The MHC molecules expression and the profiles of cell cycle were analyzed with flow cytometer. Cell proliferation was evaluated with MTT assay. ResultsAll of esophageal carcinoma cells express the gene of II-28α and IL-10β. IFN-λ induced or augmented the gene expression of antiviral molecules, 2′5′-OAS and MxA. IFN-λ enhanced the MHC class Ⅰ molecule expression. IFN-λ inhibited the growth of esophageal carcinoma cells through the regulation of cell cycle distribution. ConclusionEsophageal carcinoma cells express the IFN-λ receptor complex. IFN-λ has the antiviral, anti-proliferative and immunoregulation activity.